[PATCH] D28810: [X86][SSE] Use MOVMSK for all_of/any_of reduction patterns

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: test/CodeGen/X86/vector-compare-all_of.ll:739-746
+; SSE-NEXT:    pmovmskb %xmm0, %eax
+; SSE-NEXT:    cmpl $65535, %eax # imm = 0xFFFF
+; SSE-NEXT:    movb $-1, %al
+; SSE-NEXT:    je .LBB14_2
+; SSE-NEXT:  # BB#1:
+; SSE-NEXT:    xorl %eax, %eax
+; SSE-NEXT:  .LBB14_2:
----------------
andreadb wrote:
> I was expecting to see the usual `cmpl+movw+cmov` pattern here.
> Is it because you would end up with a conditional move of i8 quantities?
Hmm, it might be possible to lower this as:
```
        pmovmskb %xmm0, %edi
        xor %eax, %eax
        cmpl $65535, %edi
        sete %al
        negl %eax
        retq
```


Repository:
  rL LLVM

https://reviews.llvm.org/D28810